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Dash Air Question [message #279288] Sun, 07 June 2015 17:40 Go to next message
Jon payne is currently offline  Jon payne   United States
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Hi guys,

Replaced the AC compressor last fall. Too cool at the time tor service. So yesterday attempted to service with Duracool. After pulling a vacuum, verified the system was tight, I put in the first can. Then started the engine and ran at 1500 rpm. Second can in and then started the third. After a few minutes I noticed the low side pressure was not increasing and Duracool stopped going in. A waited a few more mins, still nothing going in. Shut the engine down, checked the can and is nearly full.

What would prevent the refrigerant from entering the system? As it stands now with two full cans and a bit of a third, low side pressure is less then 10 at 1500.

Any ideas what could be wrong? Expansion Valve??

Any help would be greatly appreciated! And this just three days before our first camping trip of the year!

Jon


Jon Payne
76 Palm Beach
Westfield,IN
Re: Dash Air Question [message #279291 is a reply to message #279288] Sun, 07 June 2015 18:38 Go to previous messageGo to next message
John  Sharpe is currently offline  John Sharpe   United States
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We have found that 2 cans is the right amount for our motorhomes. Too much charge also makes for insufficient cooling. What is your low side pressure? 20# or so is perfect.

John Sharpe
Porter, TX
78 Eleganza II, TBI
40 Ford Panel, TPI
Re: Dash Air Question [message #279293 is a reply to message #279291] Sun, 07 June 2015 18:47 Go to previous messageGo to next message
Jon payne is currently offline  Jon payne   United States
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John,

Low side is less than 10. Something is wrong because it won't take anymore and as you said I should have close to 20#s with 2 cans.

Jon


Jon Payne
76 Palm Beach
Westfield,IN
Re: Dash Air Question [message #279295 is a reply to message #279293] Sun, 07 June 2015 18:53 Go to previous messageGo to next message
Ken Burton is currently offline  Ken Burton   United States
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Did you let the can warm up? As it is charging it gets cold and pressure is reduced. Warm up the can and try again. Also turn the can up side down and charge it as a liquid.

Ken Burton - N9KB
76 Palm Beach
Hebron, Indiana
Re: Dash Air Question [message #279296 is a reply to message #279295] Sun, 07 June 2015 18:54 Go to previous messageGo to next message
Ken Burton is currently offline  Ken Burton   United States
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Also is the compressor clutch engaged?

Ken Burton - N9KB
76 Palm Beach
Hebron, Indiana
Re: Dash Air Question [message #279298 is a reply to message #279296] Sun, 07 June 2015 19:18 Go to previous messageGo to next message
A Hamilto is currently offline  A Hamilto   United States
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Ken Burton wrote on Sun, 07 June 2015 18:54
Also is the compressor clutch engaged?
That's a good point. At 10 pounds, the evaporator can get cold enough for the temperature switch to shut off the compressor. Even if the pressure switch is bypassed.
Re: Dash Air Question [message #279306 is a reply to message #279298] Sun, 07 June 2015 20:32 Go to previous messageGo to next message
Jon payne is currently offline  Jon payne   United States
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Compressor is engaging. I diid try again early today and still the pressure is below 10# at 1500 rpm and could not get any more refrigerant in. Also outlet temp is ~50 with OAT 75.

Other thoughts?

Jon


Jon Payne
76 Palm Beach
Westfield,IN
Re: Dash Air Question [message #279309 is a reply to message #279298] Sun, 07 June 2015 20:52 Go to previous messageGo to next message
Bullitthead is currently offline  Bullitthead   United States
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Does the Duracool come out of the charging hose when it is disconnected from the system? I have had the gasket(seal) on the charging hose get compressed enough to block the flow and lead me to believe there was something wrong with the system.

Terry Kelpien ASE Master Technician 73 Glacier 260 Smithfield, Va.
Re: Dash Air Question [message #279311 is a reply to message #279306] Sun, 07 June 2015 20:54 Go to previous messageGo to next message
A Hamilto is currently offline  A Hamilto   United States
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Jon Payne wrote on Sun, 07 June 2015 20:32
Compressor is engaging. I diid try again early today and still the pressure is below 10# at 1500 rpm and could not get any more refrigerant in. Also outlet temp is ~50 with OAT 75.

Other thoughts?

Jon
Something wrong with your filler kit? Like its not opening the Schrader valve?
Re: Dash Air Question [message #279317 is a reply to message #279311] Sun, 07 June 2015 22:15 Go to previous messageGo to next message
Ken Burton is currently offline  Ken Burton   United States
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Something wrong here. Are you sure that there is still some Duracool left in the can?

Ken Burton - N9KB
76 Palm Beach
Hebron, Indiana
Re: Dash Air Question [message #279337 is a reply to message #279317] Mon, 08 June 2015 08:12 Go to previous messageGo to next message
Jon payne is currently offline  Jon payne   United States
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Hi Ken,

I agree, something is strange here. Yes the can is nearly full. When I connect my gauges to the low side, open the valves on the gauge set it reads the system pressure. Same if I just open the can tap, I can read the pressure coming from the can. So the shrader valves appear to be working. I even pushed open with my finger the valve on the end of the hose that is attached to the can and release the refrigerant. So I know there is refrigerant in the can still.

I'm going to try again after work...maybe I'll make a video so you all can see what I am seeing.

Jon



Jon Payne
76 Palm Beach
Westfield,IN
Re: Dash Air Question [message #279339 is a reply to message #279337] Mon, 08 June 2015 08:25 Go to previous messageGo to next message
fred v is currently offline  fred v   United States
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I had the exact same thing happen with mine. I put in a Sanden compressor, new dryer, new exp. valve and flushed the evap. and condenser.

I could only get 10# on the low side. I have to assume the hoses are working as I got the first 2 cans to go in. So far it is working just fine. I get 50 Deg. air from the ducts and the compressor doesn't cycle on and off. I plan to just leave it like that as it works better than it ever has.


Fred V
'77 Royale RB 455
P'cola, Fl
Re: Dash Air Question [message #279340 is a reply to message #279288] Mon, 08 June 2015 08:41 Go to previous message
JohnL455 is currently offline  JohnL455   United States
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I'm not sure you did the can test as per Terry. Close the blue wheel (and of course red) and loosen the yelliw hose at guage set. You should get good can pressure discharge. If not, loosen the can piercing tool a bit. If the gasket is smooshed you can cut a new one from vacuum hose. Problem may be the tool not the coach. BTDT.

John Lebetski
Woodstock, IL
77 Eleganza II
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